Synthesis of Pd complexes 3.2.1.

(Figure Presented) We report the synthesis of several unique, boron-rich pincer complexes derived from mcarborane. The SeBSe and SBS pincer ligands can be synthesized via two independent synthetic routes and are metalated with Pd(II). These structures represent unique coordinating motifs, each with a Pd?B(2) bond chelated by two thio- or selenoether ligands. This class of structures serves as the first example of boron?metal pincer complexes and possesses several interesting electronic properties imposed by the m-carborane cage.

Synthesis and characterization of new Pd(II) complexes …

Synthesis and characterization of new Pd ..

N2 - Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5- pyrimidinecarbonitrile (APC) have been synthesized and characterized using elemental analysis, magnetic susceptibility, mass spectrometry, infrared (4000-200 cm-1), UV-Visible (200-1100 nm), 1H NMR and ESR spectroscopy as well as TGA analysis. The molar conductance measurements in DMSO imply non-electrolytic complexes, formulated as [M(APC)2Cl 2] where M = Co(II), Ni(II), Cu(II) and Pd(II). The infrared spectra of Co(II), Ni(II) and Cu(II) complexes indicate a bidentate type of bonding for APC through the exocyclic amino and adjacent pyrimidine nitrogen as donors whereas APC coordinated to Pd(II) ion as a monodentated ligand via a pyrimidine nitrogen donor. The magnetic measurements and the electronic absorption spectra support distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes however a square planar complex was favored for the Pd(II) complex (C 2h skeleton symmetry). In addition, we carried out B3LYP and ω-B97XD geometry optimization at 6-31G(d) basis set except for Pd(II) where we implemented LanL2DZ/6-31G(d) combined basis set. The computational results favor all trans geometrical isomers where amino N, pyrimidine N and Cl are trans to each other (structure 1). Finally, APC and its divalent metal ion complexes were screened for their antibacterial activity, and the synthesized complexes were found to be more potent antimicrobial agents than APC against one or more microbial species.

Synthesis of (NHC)Pd(salicylaldimine)Cl complexes …

Pd(II) complexes of 3 and 4 were synthesized and ..

The conversion of carbon-hydrogen (C–H) bonds into new functional groups represents a powerful strategy for the construction of organic molecules. The C–H functionalization field has transformed the way that chemists approach the synthesis of natural products and bioactive molecules, enabling fast and efficient derivatization. However, despite tremendous recent progress, selective C–H functionalization can still only be achieved in the context of a limited set of organic substrates and types of C–H sites. Our group is focused on the development of new transition metal-catalyzed C–H functionalization methods to enable the selective C–H functionalization of a variety of different substrates, ranging from simple, commodity chemicals such as benzene and methane to complex natural products and pharmaceuticals. Our work in this area includes:

Synthesis and catalytic activities of Pd II ..

AB - Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5- pyrimidinecarbonitrile (APC) have been synthesized and characterized using elemental analysis, magnetic susceptibility, mass spectrometry, infrared (4000-200 cm-1), UV-Visible (200-1100 nm), 1H NMR and ESR spectroscopy as well as TGA analysis. The molar conductance measurements in DMSO imply non-electrolytic complexes, formulated as [M(APC)2Cl 2] where M = Co(II), Ni(II), Cu(II) and Pd(II). The infrared spectra of Co(II), Ni(II) and Cu(II) complexes indicate a bidentate type of bonding for APC through the exocyclic amino and adjacent pyrimidine nitrogen as donors whereas APC coordinated to Pd(II) ion as a monodentated ligand via a pyrimidine nitrogen donor. The magnetic measurements and the electronic absorption spectra support distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes however a square planar complex was favored for the Pd(II) complex (C 2h skeleton symmetry). In addition, we carried out B3LYP and ω-B97XD geometry optimization at 6-31G(d) basis set except for Pd(II) where we implemented LanL2DZ/6-31G(d) combined basis set. The computational results favor all trans geometrical isomers where amino N, pyrimidine N and Cl are trans to each other (structure 1). Finally, APC and its divalent metal ion complexes were screened for their antibacterial activity, and the synthesized complexes were found to be more potent antimicrobial agents than APC against one or more microbial species.

Carbene-carboxylate complexes of Pd(II ..

A second research area in the Sanford laboratory focuses on the design, synthesis, and reactivity studies of high valent group ten organometallic complexes (e.g., Pd(IV), Ni(III), Ni(IV) complexes). In particular, our research probes the accessibility of these complexes and their ability to mediate challenging bond-forming reactions. These species have been implicated as reactive intermediates in a variety of catalytic transformations including C–H bond functionalization, alkene difunctionalization, and cross-coupling reactions. However, their transient nature has hindered definitive characterization of their roles in catalysis. Our group rationally designs and synthesizes model complexes of these catalytic intermediates in order to directly interrogate their reactivity towards catalytically-relevant bond-forming reactions. Ultimately, a fundamental understanding of these organometallic reactions informs the optimization of known catalytic transformations and drives the development of novel catalytic reactions. Our interests in this field include:

Pd complexes based on phosphine-linked …

Efforts to incorporate renewable energy sources such as wind and solar power into the electrical grid have increased the need for reliable and inexpensive energy storage systems. Redox flow batteries offer great promise to meet the demands of grid-scale storage. Flow batteries operating in non-aqueous media are particularly attractive (yet underdeveloped) targets, as they leverage the high cell potentials available in organic solvents such as acetonitrile. These batteries consist of dissolved solutions of redox active organic molecules or transition metal complexes. As such, the design, optimization, and testing of new battery materials is achieved through a combination of synthetic and physical organic chemistry along with electrochemical testing. Our group is focused on addressing several key challenges in the field, including: (i) the development of highly soluble organic and inorganic molecules that undergo reversible redox processes; (ii) the design of redox activate molecules capable of multiple electron transfers to enhance battery capacity; and (iii) the identification of molecules that are stable and persistent in their oxidized or reduced states to increase battery lifetimes. Our research in this area includes: